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Undelivered Events

Get to know how you can inspect and replay Undelivered Events

Managing Undelivered Events​

Despite retries, there may be situations where the endpoint simply can’t accept an event—maybe it’s offline for extended maintenance or there’s a downstream failure.

Dead Letter Queue : When maximum retries are exhausted, those undelivered events are “dead-lettered” and stored in your Subscription, abiding by retention rules. You can choose to replay a specific set of dead-lettered events (e.g., those that are time-sensitive) or replay all events within a certain window.

Dead letters are applied to both Topics and Sources, enabling you to conveniently manage both internal event processing and external requests.

How to view Undelivered Events:

View Dead letters

  1. Your Q-Flow Enviornment Dashboard provides a holistic view of Topics or Sources with dead letters. Additionally, your Subscriptions will clearly indicate if any dead letters are present, ensuring you stay informed and in control.
  2. Simply select a Subscription with dead letters and you'll be navigated to the affected Subscription.

How to inspect and replay Undelivered Events:

Inspect Dead letters

Make sure you're within a Subscription with Dead letters:

  1. Within the Subscription, you can view dead letters for a specified time period, allowing you to easily track and manage undelivered events.
  2. Choose the time period you're interested in.
  3. You can view all the dead letters within the specified period. To inspect an event, simply click on View details, which will display additional information along with the event payload.
  4. You can now replay all events within a specified time period (e.g., the last month or the last 12 hours) or selectively replay specific events if they are time-sensitive.
  5. Once you're happy, just Press Replay for the time period or for a specific event.

It’s as simple as that! You’ve successfully inspected and replayed Subscription dead letters.

Why Undelivered Events matter​

No Missed Data : You have full control over resending events once your system is healthy again.

Selective Replay : If an event is no longer relevant (e.g., a time-sensitive promo after the discount period), you don’t have to replay it, avoiding noise and confusion.